Windows - Photoshop CC or newer
You use Photoshop CC or newer on Windows.
64 bit or 32 bit?
Photoshop CC comes in two flavours, 64 bit and 32 bit. If you use a 32bit version of Windows, you only have the 32bit version, choose 32 bit below.
If you use a 64 bit version of Windows, you probably have both 64 bit and 32 bit versions of Photoshop CC. In the start menu, the 64 bit version has "(64 bit)" after the name. Which one do you use?